Idle surging

[P40E]

Anybody here install a turbo kit and afterwards get an idle surge if you blip the throttle a little bit at idle . It then falls below normal idle and the car has to catch itself before it gets too low .

Also getting idle surges when the a/c is on . Idle goes up and down a few hundred rpms at idle.

Thanks .

 

[CanadianGuy]

To provide some information that may be relevant I have seen that from people over filling the gas tank and the evap system gets messed or bad gas.

 

[P40E]

To provide some information that may be relevant I have seen that from people over filling the gas tank and the evap system gets messed or bad gas.

I haven't filled the tank up all the way yet . And I run e45 that I mix at home .

 

[Intuit]

Stock programming?

I don't yet know enough about the sensor and intake system on this vehicle, but if this were my old vehicle, I'd say the "surge" could be a result of unmetered air entering the intake.

When there's enough differential pressure to overcome resistance, electricity always takes the shortest path of least resistance. Air will do the same when given an opportunity in an engine air intake system. When air is allowed to enter from a location that the system cannot account for, (doesn't pass over a sensor,) it results with either an increase or decrease in engine RPM, depending primarily on fuel delivery conditions.

So if this started immediately after a turbo swap, you'll want to focus on everything that was, or may have been disturbed while performing the work.

 

[P40E]

It has been dyno tuned . It has a cpe intake , the older model that was fabbed to work in my 2016 .

 

[CanadianGuy]

Btw did you disconnect the battery to get the turbo on? Reason I ask is that when I disconnected mine it took a few drives for the idle to be normal. It was idling high.

 

[P40E]

It was disconnected . But I've driven probably more than 150 miles already . I've used the a/c once , and that's when I noticed the up and down with a/c on . Then noticed the idle surge if I blip the throttle at idle .

 

[1azst]

I have a dhm kit and mine does this every time I load a different tune. Ac makes it worse. To fix it, I let it idle for five minutes with ac off, another five with ac on, fan on low. Lastly, five more on max ac, fan cranked. It seams to take awhile to relearn it.